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DTC U0121 ABS/ASC CAN timeout
 
 
caution
  • If DTC U0121 is set in the BSW-ECU (slave), always diagnose the CAN bus line.
  • Before replacing the ECU, ensure that the power supply circuit, the ground circuit and the communication circuit are normal.
 
 
OPERATION
The BSW-ECU (slave) communicates with the ASC-ECU via the gateway-ECU and the BSW-ECU (master) over CAN bus lines.
 
 
CHECK CONDITION
Electric motor switch is in the ON position.
 
 
DIAGNOSTIC FUNCTION AND TROUBLE JUDGMENT
If the BSW-ECU (slave) cannot receive any signal from the ASC-ECU for at least 2.5 seconds, the ECU sets DTC U0121.
 
 
TROUBLESHOOTING HINTS
  • Power supply to the ASC-ECU fails
  • Malfunction of the ASC-ECU
  • Power supply to the gateway-ECU fails
  • Malfunction of the gateway-ECU
  • Malfunction of the BSW-ECU (master/slave)
  • Malfunction of the CAN bus
  • Malfunction of the local CAN bus
 
 
DIAGNOSIS
1. Using scan tool (M.U.T.-IIISE), read the BSW-ECU (master) DTC [Check whether DTC C2332 and/or U0121 are set in the BSW-ECU (master)].
2. Using scan tool (M.U.T.-IIISE), read the BSW-ECU (slave) DTC again.